Archives de catégorie : biology+acidification

Coral Adaptation and Epigenetics

by Rud Itsvan, November 17, 2018 in WUWT


WUWT has posted several excellent articles by Jim Steele on how global warming alarmism uses corals as the poster child for warming and acidifying oceans, none of which is scientifically justified. A brief review follows, calling attention to a recently discovered additional adaptation mechanism not covered AFAIK by Jim Steele’s posts. The motivation for this post was triggered by a recent lunch with newish neighbor Charles the Moderator (CtM), and his sharing many wonderful underwater photographs of the coral reef he now dives frequently off Pompano Beach (same reef system as off Fort Lauderdale, just a few miles further north and more conveniently onshore).

Proof that Corals are Adapting to Warming Temperatures

by Coles et al., November, 11,  2018 in CO2Science


In light of the above findings, Coles et al. state the obvious, that the corals “were able to withstand elevated temperatures (31.4 °C) for a longer period of time in the current 2017 experiment” compared to the 1970 study. Consequently, they conclude that their results “indicate a shift in the temperature threshold tolerance of these corals to a 31-day exposure to 31.4 °C,” which findings “provide the first evidence of coral acclimatization or adaptation to increasing ocean temperatures.” And that observational reality should hold great bearing on the status and health of coral reefs in response to future climate change. If temperatures rise in the future, clearly, as living organisms, corals can (and do!) adapt. Alarmist predictions of their fast and ensuing demise due to global warming should not be taken too seriously.

Holocene temperature in the Iberian Peninsula reconstructed studying insect subfossils

by University of Barcelona, November 9, 2018 in ScienceDaily


Regional differences regarding other reconstructions

The results of the study show a temperature rise in the beginning of the Holocene, reaching the highest values in the Holocene Climate Optimum (about 7,800 years ago). There are also high temperatures until about 6,000 years ago, when a decline of temperature started and led to the lowest values in the first stage of the late Holocene (about 4,200 and 2,000 years ago).

Last, researchers detected a rise of temperatures over the two last millenniums, but they state they have to be careful with these data. “We cannot guarantee the observed rise in the reconstruction results from a temperature rise only, we cannot rule out other variables that can influence at other levels, such as the gradual increase of the anthropic activity in the area, which can change the community of Chironomidae to species that adapt to higher temperatures, but there are also human influence indicators,” says Narcís Prat.

Although these conclusions can coincide with other paleoclimate reconstructions, results also highlight some divergences at a regional level. “These differences can occur due the fact that some indicators point out to different seasonal signs. Therefore, Chironomidae are indicators of temperature in summer, while others such as chrysophites or alkenones are related to winter/spring temperatures,” notes the researcher.

A tool to evaluate climate trends

Biodiversité, le vrai, le faux et l’incertain

by Prof. Paul Berth, 4 novembre 2018 in ScienceClimatEnergie


Le 30 octobre 2018 sortait le dernier rapport du WWF[1] concernant l’état de la biodiversité (voir ici). Les données obtenues sont très préoccupantes. De nombreux médias ont bien entendu présenté ce rapport de façon très alarmiste en exagérant certains points. Le but du présent article est de remettre les pendules à l’heure, en démêlant le vrai du faux et en présentant certaines incertitudes.

1. Que dit exactement le rapport du WWF? Le rapport du WWF nous dit que globalement, entre 1970 et 2014, l’index LPI (Living Planet Index) a chuté de 60% (Figure 1). Il n’est pas question ici de mettre en doute les résultats obtenus par le WWF mais simplement de les mettre en perspective. L’index LPI est calculé en tenant compte du nombre d’individus pour plusieurs espèces. Au total, ce sont 4 005 espèces qui ont été considérées, réparties en 16 704 populations (il peut donc y avoir plusieurs populations pour une même espèce). Ces populations proviennent de tous les continents. Pour toutes les espèces prises en compte le nombre d’individus a été estimé, puis des sommes ont été établies.

Large stretches of coral reefs can be rehabilitated

by University of California – Davis, September 27, 2018 in ScienceDaily


For the study, published this week in the journal Restoration Ecology, researchers installed 11,000 small, hexagonal structures called “spiders” across 5 acres of reef in the center of Indonesia’s Coral Triangle. Coral diversity is the highest on Earth in that region but is threatened by human activity, including overfishing, pollution and climate change.

Between 2013 and 2015, researchers attached coral fragments to the structures, which also stabilized rubble and allowed for water to flow through freely.

A CORAL SUCCESS STORY

Live coral cover on the structures increased from less than 10 percent to more than 60 percent. This was more than what was reported for reefs in many other areas of the Coral Triangle, at a cost of about $25 per square meter.

Les coraux blanchissent depuis très longtemps

by Prof. Dr. Paul Berth, 5  septembre 2018, in ScienceClimatEnergie


Le blanchissement des coraux est un phénomène dont on entend souvent parler dans les médias. Il s’agirait d’un grave problème environnemental, dont la fréquence augmente, et qui pourrait mener à la perte totale des récifs coralliens. Le réchauffement climatique global, qui serait causé par l’augmentation de la concentration atmosphérique en CO2 est, bien entendu, pointé du doigt. Cependant, le blanchissement des coraux n’est-il pas un phénomène très ancien? Est-il seulement causé par des variations de température? Quel recul avons-nous à ce sujet? Une récente publication de Nicholas Kamenos et Sebastian Hennige, deux chercheurs anglais des Universités de Glasgow et d’Édimbourg, apporte de nouveaux éléments.

Remember when they told us coral bleaching was a sure result of recent man-made global warming? Never mind.

by Anthony Watts, August 17, 2018 in WUWT


From the “science eventually self-corrects” department, new science showing coral bleaching of the Great Barrier Reef is a centuries-old problem, well before “climate change” became a buzzword and rising CO2 levels were blamed.

Marc Hendrickx writes:

New paper shows coral bleaching in GBR extending back 400+ years.

Glacier depth affects plankton blooms off Greenland

by Helmholtz Centre for Ocean Research Kiel (GEOMAR), Auhsut 14, 2018 in ScienceDaily


The unusual timing of highly-productive summer plankton blooms off Greenland indicates a connection between increasing amounts of meltwater and nutrients in these coastal waters. Researchers now show that this connection exists, but is much more complex than widely supposed. Whether increasing meltwater has a positive or negative effect on summertime phytoplankton depends on the depth at which a glacier sits in the ocean.

“So, the study shows that further melting of Greenland’s glaciers only leads to stronger summer plankton blooms under very specific conditions, an effect that will ultimately end with very extensive further melting,” Hopwood summarizes the results of the study.

Ice sheets of the last ice age seeded the ocean with essential nutrient silica

by University of Bristol, August 10, 2018 in ScienceDaily


Silica is needed by a group of marine algae (the microscopic plants of the oceans) called diatoms, who use it to build their glassy cell walls (known as frustules).

These plankton take up globally significant amounts of carbon — they remove carbon dioxide from the atmosphere via photosynthesis, and act as a natural carbon sink when they die and fall to the bottom of the ocean — and form the base of the marine food chain.

The researchers are also planning to use more complex and realistic computer models to delve deeper into the potential changes in the global silica cycle since the last glacial maximum. These might include more accurate representations of ocean currents, recycling of silica in the water column, and potential changes to the marine algal community.

New Study Shows Some Corals Might Adapt to Climate Changes

by Anthony Watts, August 4, 2018 in WUWT


UM Rosenstiel School-led study exposes two threatened corals to future climate change conditions

MIAMI—New research shows that not all corals respond the same to changes in climate. The University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science-led study looked at the sensitivity of two types of corals found in Florida and the Caribbean and found that one of them—mountainous star coral—possesses an adaptation that allows it to survive under high temperatures and acidity conditions.

“Stressful periods of high temperature and increasingly acidic conditions are becoming more frequent and longer lasting in Florida waters,” said Chris Langdon, marine biology and ecology professor and lead author on the new study. “However, we found that not all coral species are equally sensitive to climate change and there’s hope that some species that seemed doomed may yet develop adaptations that will allow them to survive as well.”

See also (in French) here and  here

In the ocean’s twilight zone, tiny organisms may have giant effect on Earth’s carbon cycle

by Florida State University, July 18, 2018 in ScienceDaily


Deep in the ocean’s twilight zone, swarms of ravenous single-celled organisms may be altering Earth’s carbon cycle in ways scientists never expected, according to a new study from Florida State University researchers.

In the area 100 to 1,000 meters below the ocean’s surface — dubbed the twilight zone because of its largely impenetrable darkness — scientists found that tiny organisms called phaeodarians are consuming sinking, carbon-rich particles before they settle on the seabed, where they would otherwise be stored and sequestered from the atmosphere for millennia.

This discovery, researchers suggest, could indicate the need for a re-evaluation of how carbon circulates throughout the ocean, and a new appraisal of the role these microorganisms might play in Earth’s shifting climate.

The findings were published in the journal Limnology and Oceanography.

The sixth mass genesis? New species are coming into existence faster than ever thanks to humans

by Prof. Chris D. Thomas, July 10, 2017 in TheConversation


Animals and plants are seemingly disappearing faster than at any time since the dinosaurs died out, 66m years ago. The death knell tolls for life on Earth. Rhinos will soon be gone unless we defend them, Mexico’s final few Vaquita porpoises are drowning in fishing nets, and in America, Franklin trees survive only in parks and gardens.

Yet the survivors are taking advantage of new opportunities created by humans. Many are spreading into new parts of the world, adapting to new conditions, and even evolving into new species … (…)

Corals use epigenetic tricks to adapt to warmer and “more acidic” water

by JoNova, June 12, 2018 inJoNovaBlog


After half a billion million years of climate change, I’m shocked, shocked I tell you, that life on Earth (and specifically corals) have so many ways to cope with the climate changing. After all, it’s natural (if you are trained by Greenpeace) to assume that corals can only survive in a world with one constant stable temperature just like they never had.

One more tool in the coral-reef-workshop

Corals don’t just have a tool-box, they have a Home Depot Warehouse. h/t to GWPF

(..)

More Proof of a Biological Control on Coral Calcification

by Ross C.L. et al., 2017, June 10, 2018 in CO2Science


The global increase in the atmosphere’s CO2 content has been hypothesized to possess the potential to harm coral reefs directly. By inducing changes in ocean water chemistry that can lead to reductions in the calcium carbonate saturation state of seawater (Ω), it has been predicted that elevated levels of atmospheric CO2 may reduce rates of coral calcification, possibly leading to slower-growing — and, therefore, weaker — coral skeletons, and in some cases even death.

As we have previously pointed out on our website, however (see The End of the Ocean Acidification Scare for Corals and A Coral’s Biological Control of its Calcifying Medium to Favor Skeletal Growth), such projections often fail to account for the fact that coral calcification is a biologically mediated process, and that out in the real world, living organisms tend to find ways to meet and overcome the many challenges they face; and coral calcification in response to ocean acidification is no exception.

(…)

See also in French